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From a post I made to a fellow lister:
Info for the masses.
Suf Daddy wrote on September15th, 2004 11:09 AM:
Maybe NH has more than two, but it seems like everyone's trying them out. I watched a few stops but they gave verbal warnings.
So now I guess the test phase is over, hence some with citations.
I have four doppler units here and the KR-11 Vascar gizmo which is nearly identical to the NH "Sky timer" they use.
The owners manual goes into several sections of operation and use. Its here they seem to breeze over points which they make about cautions of use.
ProLAser 2 no through windows, but Pro laser 3 glass, snow, rain anything. I don't believe it. Kustoms says alot of things.
Kustoms POP (radar) feature is electronically calculated faster that the "clock" speed of their processor. They tout it as a selling point, then say in the manual don't use it for citing the speeder.
COme on...........
Aorund 1990 the laser was "ABLE" pick a car out of a lane. That's BS at 1,000 feet or more since the current 4th generation lidar/laser units are 3' wide at 1,000 feet.
This led New Jersey to ban lidar use over 1,000 feet. IMHO.
NH has been using them exceeding 2,000 feet in my observed testing. They "paint" you far away then confront you as you pass.
Too much error IMHO.
Page 7 of Pro III:
"Because of the narrow beam width and minimal expansion, the laser is used in surveying since a small object can be targeted at great distance." THEN Page 8:
ProLAser II square beam 3'x3' at 1,000 ft
"Beam expressed as 3.0 mr x 3.0 mr or about 0.172 degrees."
convert degrees to a fraction of: 0.00300198 "times the distance to the target."
Pick 700' x .003 and you get a beam width of 2.1'
Try 1,700" and you get 5.10' (square) which is a labratory test because the (smoke, dust, rain etc.) particles in the air scatter light...."flair" it out farther.
They measure DISTANCE not speed. page 8.
The device measures "pulses" around 200 a second. and compares them to returned pulses.
The calculuation is done in 5 MILLIseconds.
then based on that calc (page 10) "the computer calculates the average speed."
It really looks for a minimum of 70 pulses to make a reading.
THEN
the unit uses "various error trapping" software (algorythium) to further compute a reading.
The technique is not using a simple average, but "LEAST SQUARES, another form of averaging is used." page 10.
Now in Doppler radar, you have to have a suffient tracking history.
Now how does that work with the Laser?
more to come this computer crashes.
-Suf Daddy